Where are you located? Do you mean "because of the heat" needed when they are young? I'm in Northern Vermont and am putting chicks out at 3 weeks old now. Have a group of cockerels that have been outside since Friday and loving it. They only had wing feathers and some starting on shoulders but the weather has definitely broken into full summer now and they are perfectly fine. The first two weeks they are very heat dependent but do quite well there after. Heck, yesterday hit 80 F here so had garage door open and lamp for brooder turned off. Forgot all about it until giving food and water this morning. Those week old chicks were not even huddled together. Garage got down to 60 F by this morning.
All I can say for space with meat birds is get a chest freezer. I'd think you'd want minimum 150 sqft for them to exercise enough for health but personally have not done ConishX. We do dual purpose here, have a lot of cockerels growing, and will be searching craigslist for a good used freezer this summer. It will be my own freezer and others in house will have to keep their stuff out. Need the space open for birds over summer and fall and then bee hive frames after the honey is spun out. When I need the freezer space any boxes of popsicles or whatnot in the way will uncerimonially be tossed. They've been warned.